Rider exerciser



FIG. 1 is a perspective view thereof;

FIG. 2 is a side view thereof;

FIG. 3 is the other side view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines illustrate portions of the rider exerciser which form no part of the claimed design. 

The ornamental design for a rider exerciser, as shown and described. 